If you are interested in scaling agility, I read a great book by Dean Leffingwell that really examines bringing agile up above the Team level and involving the entire organization at a large scale. Aside from the basics, it gets into using agile for architectural epics, program planning, investment decisions:

The book also references a website that he and a group of others have put together which provides a free framework (SAFe), and I’ve used pieces of that site for explaining to executives or program managers how to introduce agile to their level of the business.